Title : The Energy Budget at the Earth's Surface: Photosynthesis Under Field Condition: Solar Radiation Balance and Photosynthetic Efficiency.

Descriptive Note : Interim rept.,

Corporate Author : AGRICULTURAL RESEARCH SERVICE ITHACA N Y

Personal Author(s) : YOCUM,C.S. ; ALLEN,L.H. ; LEMON,E.R.

Report Date : JUL 1962

Pagination or Media Count : 1

Abstract : A spectrophotometer suitable for field use in measuring solar radiation in the range between 0.3 an 1.0 microns is escribed. Compo e s of y em include a direction integrator, a dispersing element, a detector, an amplifier,AND A RECORDER WHICH PLOTS SYSTEM RESPONSE VS WAVELENGTH. M EASUREMENTS OF T SPECTRAL CHARACTERISTICS OF ). TO !.) MICRON RA IATION P NETR I G A DENSE STAND OF CORN ARE REPORTED. Tran mission ata re illus ra d for two widely differing conditions--a clear d y and a heavily overcast day. Transmission, reflection, and ab orp ion dat for a single corn l af are included. Measurements indicate hat in t e p o o ynt ically active part of the spectrum, 10 to 14 percent of the incident radiation reaches the 40-cm level in corn that is 300 cm high. Calculations indicate maximum thermal efficiency of photosynthesis under the experimental conditions to be 40 percent of the yield obtained from laboratory grown chlorella. (Author)